Flexible polyurethane foam can be made to have flame resistant, insulating, and energy-absorbing properties. It has had a wide variety of end uses, ranging from a structural building material to a shock-mitigating material in the closure of submarine missile launch systems. Polyurethane structural foams are expensive however, and require addition of flame retardants to make them fire resistant. Also, polyurethane foam has not met all the breathability and load-deflection response requirements necessary to accelerate the closure shell in a missile launch system to launch velocity, without damaging the missile nose during launch.
Phenolic resin foams have been taught by D'Alessandro, in U.S. Pat. No. 3,389,094. There, an extremely small closed cell, abrasion resistant, water resistant, flame resistant foam, with trapped blowing agent, was produced. D'Alessandro combined specific polyhalogenated saturated fluorocarbon blowing agents, with a phenolic resole resin, a nonionic surfactant and a strong acid catalytic condensation agent. Penfold, in U.S. Pat. No. 3,639,303, taught use of both mononuclear phenols and polynuclear diphenols, to provide phenolic resole resins which were reacted at about 50.degree. C to 60.degree. C, with a low boiling hydrocarbon or fluorocarbon blowing agent, a nonionic surfactant and a mineral acid catalytic condensation agent. This provided a foam with good toughness, abrasion resistance and thermal insulation properties, useful in structural applications such as roof decks. None of these patents, however, provide a method of controlling phenolic resole foam compressive strength and breathability, to provide foams having a variety of properties and end uses, and having not only flame resistant, insulating and abrasion resistant properties, but also high compressive strength properties.